There are about 260 living species of monkeys on Earth, divided into New World monkeys from Central and South America, and Old World monkeys from Asia and Africa. Almost all New World monkeys have prehensile tails, but Old World monkeys have either non-prehensile tails, or no visible tails.

Although it is common to distinguish apes from monkeys, apes are catarrhines, and catarrhines are monkeys. So, apes are monkeys.